1. Field of the Invention
The invention lies in the field of lifting equipment. The invention relates to a lifting device used to lift motorcycles or other suitable loads, especially suitable for loads having a low ground clearance. The lifting device of the present invention provides additional stability and improved safety. Also provided is an adjustable stabilizing element that can be used with the lifting device of the present invention or with conventional jacks, particularly jacks for motorcycles and/or all-terrain vehicles.
2. Description of the Related Art
Generally, different types of jacks exist in the prior art for lifting motorcycles or similar loads, such as hydraulic jacks, articulated jacks, and screw operated jacks.
U.S. Pat. No. 6,168,138 to Dhein describes a universal lift system for use in combination with a conventional hydraulic floor jack. The universal lift system replaces the mounting bracket on the floor jack with a substantially H-shaped attachment device having a kingpin that fits into a hole on the conventional jack. The lift system also includes a separate stabilizing device that attaches to the bottom of the floor jack. The lift system has a third separate part called an adjustable support device. The lift system is particularly suitable for lifting and supporting two-wheeled motorized vehicles. The universal lift system, however, is not configured to lift and support objects having a small floor-to-object clearance.
U.S. Pat. No. 4,457,492 to Lahti discloses a lifting apparatus for lifting a load, such as a motorcycle. The Lahti apparatus uses a lever operable cam to raise or lower the load. The Lahti apparatus, however, is not suitable for lifting and supporting objects having a small floor-to-object clearance. In fact, the clearance must be greater than the overall height of the Lahti apparatus, to wit, from the casters to the top of the load support.
U.S. Pat. No. 5,588,639 to Holman teaches a single-person operable support structure for lifting a motorcycle in combination with a common hydraulic floor jack. The support structure can support a motorcycle on the common jack in a variety of angular orientations. The Holman structure is limited to objects having a floor-to-bottom clearance that is greater than the sum of the height of the Holman retrofit structure plus the height of the common floor jack.
U.S. Pat. No. 5,601,277 to Larson is drawn to a two-piece jacking system for two-wheeled vehicles including a jacking mechanism and an adjustable separate support stand. Both the jacking mechanism and the stand have adjustable threaded bolts for adjusting the devices when they are placed on uneven support surfaces. Again, the Larson structure is limited to objects having a floor-to-bottom clearance that is greater than the height of the Larson jacking mechanism.
U.S. Pat. No. 5,769,396 to Tischendorf discloses a multi-purpose motorcycle lift somewhat similar to the Lahti apparatus. A foot-operated stirrup is directly connected to one, of a pair of lifting beams connected to support bars. When the stirrup is pressed downwards, the lifting beams are forced to pivot and raise the support bars, with the motorcycle, until the lifting beams are moved past the vertical. Again, the Tischendorf structure is limited to raising objects having a floor-to-bottom clearance that is greater than the height of the entire Tischendorf structure before it is rotated to raise the lifting beams. The lifting beams are individually adjustable to correspond to lifting points on the motorcycle that are uneven with respect to ground.
U.S. Pat. No. 4,077,607 to Lovelady describes a complex service rack for motorcycles, the rack having a platform to support the motorcycle wheels including a ramp and a clamp for holding one of the motorcycle wheels therein. The servicing rack is almost as large as the motorcycle and is not configured to fit under objects having a small floor-to-object bottom clearance.
Some common problems exist among these prior art jacks. One problem is that the minimum required clearance height between the ground and the load is five inches or more. Newly-manufactured motorcycles, however, may only have two or three inches of ground clearance. Therefore, to utilize commonly available lifting devices, the user is required to drive or push the motorcycle onto supporting planks or blocks to artificially create the necessary minimum clearance for the prior art lifting device. Such an operation can be difficult and dangerous. It is, therefore, desirable to provide a low-profile lifting device that can accommodate the required low clearance without any extra lifting operation.
Additionally, the considerable extension of a load over a jack very often causes the problem of load instability. It is, therefore, desirable to provide additional stability when lifting the load. Additional stability is especially necessary for a small profile jack that is used on motorcycles having a low ground clearance.
Conventional jacks typically have flat lifting surfaces. Some motorcycles, however, do not have uniformly flat lower surfaces. Alternatively, the lifting surfaces may not exist below the center of gravity of the motorcycle. It is, therefore, necessary to provide a supporting device that is adjustable according to different lower surfaces of the motorcycle.
In general, hydraulic jacks may be subjected to unexpected loss of hydraulic pressure. Such loss of pressure may be dangerous, and could cause damage or injury. Some of the existing jacks on the market have employed safety devices to reduce pressure loss hazards. Such safety devices are generally of the nature of pawls that engage fixed xe2x80x9cteethxe2x80x9d on the jack frame. However, such devices suffer from the drawback that the user must remember to engage the safety device.
Another drawback of these devices lies in the release of the safety devices. Due to the symmetrical nature of these jacks, it is common practice to employ a safety pawl on either side of the device. When releasing such a safety device, therefore, the user must retract one pawl on each side of the jack while simultaneously rotating the release valve to lower the jack. The great difficulty in performing three operations simultaneously, without assistance from another person, leads to non-use of the safety device. It is, therefore, very important to provide a safety device that can be released easily by a single operator.
It is accordingly an object of the present invention to provide an adjustable receiving element that may be used to lift loads that may not be conveniently lifted by a lifting device with a typical flat lifting surface. The adjustable receiving element can be used either as an attachment to an existing lifting device or incorporated into a lifting device.
With the foregoing and other objects in view, an adapter is provided which allows a jack to engage a work piece variably within three dimensions of connection, and to maintain the work piece in a stable horizontal contact during the entire lift by the jack. Specifically, the adapter allows a holding connection with the work piece in at least three unrelated points of contact within three dimensions, such that the points of contact are not within a single horizontal line or plane yet each of points of contact equally bear the load of the work piece.
In the preferred embodiment of the present invention, each of several connection arms within an adapter is individually adjustable within three-degrees-of-movement. The removable adapter assembly of the preferred embodiment of the present invention, includes an adapter frame having threaded holes and a connector for releasably attaching the frame to the head of the jack, and three-degree-of-movement adapter arms rotatably inserted into a respective one of the threaded holes for raising and lowering each of the arms with respect to the frame, the arms each having a threaded portion with a top end, a horizontal head portion having a closed slot, the head portion fixedly attached to the top end of the threaded portion, and a cushioned receiver rotatably and slidably mounted in the slot.
In accordance with an added feature of the preferred embodiment of the present invention, the adapter frame is rectangular, in particular, square.
In accordance with another feature of the preferred embodiment of the present invention, the threaded holes are four threaded holes and the three-degree-of-movement adapter arms are four three-degree-of-movement adapter arms.
In accordance with an additional feature of the preferred embodiment of the present invention, the connector includes a second set of holes formed in the frame and a fastener for removably fastening the frame to the head of the jack.
In accordance with a further feature of the preferred embodiment of the present invention, each of the second set of holes is formed at each corner of the frame.
In accordance with another added feature of the preferred embodiment of the present invention, each of the second set of holes is threaded.
In accordance with another additional feature of the preferred embodiment of the present invention, each of the second set of holes has center points and the head of the jack has securing holes with centers aligned with the center points.
In accordance with another further feature of the preferred embodiment of the present invention, each of the second set of holes is threaded and the fastener is a threaded bolt.
In accordance with a further added feature of the preferred embodiment of the present invention, the securing holes have a diameter and the threaded bolt has a head wider than the diameter.
In accordance with a further additional feature of the preferred embodiment of the present invention, the head has wing extensions.
In accordance with an added feature of the preferred embodiment of the present invention, each of the securing holes is threaded and the fastener is a threaded bolt.
In accordance with an additional feature of the preferred embodiment of the present invention, each of the second set of holes has a diameter and the threaded bolt has a head wider than the diameter.
According to a concomitant feature of the preferred embodiment of the present invention, the cushioned receiver has a sliding and rotating connector with a top side and a V-shaped head with a bottom of the head attached to the top side of the sliding and rotating connector.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a lifting device assembly, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.